Unilateral spinal anesthesia

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Unilateral spinal anesthesia

• Report by R2 Lan,Cheng-Yen
• National Taiwan University Hospital
• Department of Anesthesiology

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I want to know

• ????unilateral spinal anesthesia?
• ??nondependent part???,??hypobaric
  anesthetic????isobaric anesthetic ??

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Unilateral spinal anesthesia

• Fifty years ago, under unilateral spinal
  anaesthesia.
• Initially, hypobaric local anaesthetics were used
  followed by hyperbaric solutions
• Curr. Opin.
  Anaesthesiology 1998115,511-5

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Advantage over conventional spinal anesthesia

• Lower incidence of haemodynamic complications
• More selective block on the operated side and
  avoid unnecessary paralysis of the non-operated
  side.
• Better mobilization during the recovery period
• Patients satisfaction
• Revista
  Brasileira de Anestesiologia 2003535
• CAN J
  ANESTH 2005 52 9 pp 958962

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Is It possible?

• Intersegmental distance between spinal nerves
  20-25 mm
• Distance between spinal nerve roots 10-13 mm
• Patient-dependent factors
• Controllable factors
• Curr. Opin.
  Anaesthesiology 1998115,511-5

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How to achieve?

• Lateral decubitus position
• Low local anesthetic doses
• Pencil point needle orientation
• Slow local anesthetic injection
• Revista Brasileira de
  Anestesiologia
• Vol. 53, No 5,
  Setembro - Outubro, 2003

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Slow injection

• How is the rate?
• What is the success rate ?

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• Air-buffered technique
• Depending on the patients height, 1.4 to1.7 mL
  hyperbaric bupivacaine 0.5was injected
• Lateral decubitus position for 30 min
• Group I0.5ml/min
• Group II7.5ml/min

Reg Anesth Pain Med 200126420-427.
9

• Strictly unilateral anesthesia was achieved in
  40 of the cases
• No clinical relevant differences in blood
  pressure and heart rate

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Low dose

• The effect?
• Hyperbaric and hypobaric solution

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• 7.5 mg (1.5 mL) hyperbaric bupivacaine 0.5
  (density 1.026 g/mL), injected speed 0.05 mL/s
• 7.5 mg (4.2 mL) hypobaric bupivacaine 0.18
  (density 0.997 g/mL), injected speed0.05 mL/s
• hypobaric1.8 mL plain bupivacaine 0.5
• diluted with sterile water up to 5 mL
• Fix 15mins

Reg Anesth and Pain Med, 2004291, pp 1722
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Hypobaric solution

• Density ,specific gravity, baricity
• CSFs specific gravity1.0069 g/ml
• 0.1-0.33 tetracaine with sterile
  water(baricitylt0.9977)
• Warmed 0.5 bupivacaine to 37?,
  density0.9993g/ml
• Millers Anesthesia 6th
  P.1667-1668

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Isobaric bupivacaine 3.5 mL(17.5 mg) of plain
bupivacaine 0.5 diluted with normal saline to a
total of 5 mL measured density at 37C was
0.999406 g/mL.

• Hypobaric bupivacaine 3.5 mL (17.5 mg) of plain
  bupivacaine 0.5 diluted with distilled water, to
  a total of 5 mL measured density at 37C was
  0.997302 g/mL.

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Hypobaric spinal anesthesia for THR

• 17.5 mg of hypobaric bupivacaine, compared with
  the identical dose of isobaric bupivacaine,
  prolonged sensory regression to L2 and delayed
  the use of first analgesic, without further
  compromising systemic hemodynamics.
• 45 minutes longer duration of spinal block is
  clinically relevant and increases the reliability
  of hypobaric spinal anesthesia for this type of
  surgical procedure.

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Clinically feasible approach

• Slow (1 ml/min) and steady injection
• Reduced dose of a non-isobaric local anaesthetic
  via a directional spinal needle with opening to
  the side of surgery
• Lateral decubitus position for 20 min
• Slight repositioning (5-10) to achieve the
  required block level.
• Hypobaric solution
• Curr. Opin. Anaesthesiology
  1998115,511-5

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Thanks for your attention!